Attachment 133763 Details for Bug 102334 – Fix wake_affine regression

[patch] Fix wake_affine regression

0001-sched.patch (text/plain), 3.20 KB, created by Chris Wilson on 2017-08-24 21:20:41 UTC

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Creator: Chris Wilson

Created: 2017-08-24 21:20:41 UTC

Size: 3.20 KB

patch

obsolete

>From b4d610feb2242c9d43387e02c7529b7c14c2b683 Mon Sep 17 00:00:00 2001
>From: Chris Wilson <chris@chris-wilson.co.uk>
>Date: Thu, 24 Aug 2017 22:03:39 +0100
>Subject: [PATCH] sched!
>
>Fixes: 3fed382b46ba ("sched/numa: Implement NUMA node level wake_affine()")
>Cc: Rik van Riel <riel@redhat.com>
>Cc: Mel Gorman <mgorman@suse.de>
>Cc: Mike Galbraith <efault@gmx.de>
>Cc: Peter Zijlstra <peterz@infradead.org>
>Cc: Thomas Gleixner <tglx@linutronix.de>
>Cc: Ingo Molnar <mingo@kernel.org>
>---
> kernel/sched/fair.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 53 insertions(+), 6 deletions(-)
>
>diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
>index c95880e216f6..912ff81a0f3f 100644
>--- a/kernel/sched/fair.c
>+++ b/kernel/sched/fair.c
>@@ -123,6 +123,11 @@ int __weak arch_asym_cpu_priority(int cpu)
> unsigned int sysctl_sched_cfs_bandwidth_slice		= 5000UL;
> #endif
> 
>+static unsigned long weighted_cpuload(const int cpu);
>+static unsigned long source_load(int cpu, int type);
>+static unsigned long target_load(int cpu, int type);
>+static unsigned long capacity_of(int cpu);
>+
> /*
>  * The margin used when comparing utilization with CPU capacity:
>  * util * margin < capacity * 1024
>@@ -1378,11 +1383,6 @@ bool should_numa_migrate_memory(struct task_struct *p, struct page * page,
> 	       group_faults_cpu(ng, src_nid) * group_faults(p, dst_nid) * 4;
> }
> 
>-static unsigned long weighted_cpuload(const int cpu);
>-static unsigned long source_load(int cpu, int type);
>-static unsigned long target_load(int cpu, int type);
>-static unsigned long capacity_of(int cpu);
>-
> /* Cached statistics for all CPUs within a node */
> struct numa_stats {
> 	unsigned long nr_running;
>@@ -2657,7 +2657,54 @@ static inline bool numa_wake_affine(struct sched_domain *sd,
> 				    struct task_struct *p, int this_cpu,
> 				    int prev_cpu, int sync)
> {
>-	return true;
>+	s64 this_eff_load, prev_eff_load;
>+	s64 this_load, prev_load;
>+	unsigned long task_load;
>+	int idx;
>+
>+	idx       = sd->wake_idx;
>+	prev_load = source_load(prev_cpu, idx);
>+	this_load = target_load(this_cpu, idx);
>+	task_load = task_h_load(p);
>+
>+	/*
>+	 * If sync wakeup then subtract the (maximum possible)
>+	 * effect of the currently running task from the load
>+	 * of the current CPU:
>+	 */
>+	if (sync) {
>+		unsigned long current_load = task_h_load(current);
>+
>+		if (this_load > current_load)
>+			this_load -= current_load;
>+		else
>+			this_load = 0;
>+	}
>+
>+	/*
>+	 * In low-load situations, where prev_cpu is idle and this_cpu is idle
>+	 * due to the sync cause above having dropped this_load to 0, we'll
>+	 * always have an imbalance, but there's really nothing you can do
>+	 * about that, so that's good too.
>+	 *
>+	 * Otherwise check if either cpus are near enough in load to allow this
>+	 * task to be woken on this_cpu.
>+	 */
>+	if (prev_load > task_load) {
>+		prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2;
>+		prev_eff_load *= capacity_of(this_cpu);
>+		prev_eff_load *= prev_load - task_load;
>+	} else
>+		return false;
>+
>+	if (this_load > 0) {
>+		this_eff_load = 100;
>+		this_eff_load *= capacity_of(prev_cpu);
>+		this_eff_load *= this_load + task_load;
>+	} else
>+		return true;
>+
>+	return this_eff_load <= prev_eff_load;
> }
> #endif /* !SMP */
> #endif /* CONFIG_NUMA_BALANCING */
>-- 
>2.14.1
>

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